1. Field of the Invention
The present invention relates to an information collection apparatus for collecting information data transmitted from a photographing apparatus and information acquisition apparatuses.
2. Description of the Related Art
Recently, sensing-network systems including a network and a plurality of sensors connected thereto are receiving attention. For example, Nikkei Electronics, Jul. 15, 2002, pp. 99-129, discloses several sensing-network systems. One of the example sensing-network systems disclosed in the above-described document includes numerous sensors distributed in a forest for collecting information on the forest, such as amount of oxygen generated, amount of CO2 absorbed, temperature, humidity, and so forth. This sensing-network system can be used for early detection of a forest fire and CO2-emission right transactions.
Further, sensor modules equipped with communication functions called Mote have been studied at the University of California, Berkeley. Although each Mote is relatively small, with each edge being about several centimeters long or less, Mote includes a physical sensor for measuring a predetermined physical quantity such as temperature, humidity, and so forth, a data-processing unit, and a wireless-communications unit are provided therein. Further, Mote has an ad-hoc communication function for performing wireless communications, so as to automatically determine or change a communication route.
Downsizing sensor modules allows for significant increased flexibility in determining position and methods for installing sensors, as shown in the above-described example. That is to say, it becomes possible to distribute the sensors in a predetermined environment and attach or set in predetermined unit of a building or other products.
On the other hand, known systems including an image-pickup device and a plurality of sensors were disclosed in Japanese Patent Laid-Open No. 8-18943, corresponding U.S. Pat. No. 5,844,599 (hereinafter referred to as Patent Document 1), Japanese Patent Laid-Open No. 2003-121195, corresponding U.S. patent application Ser. No. 2003032436 (hereinafter referred to as Patent Document 2), and so forth. According to Patent Document 1, a plurality of speech-activated transmitters is used for detecting the position of an effective speaker and the attitude of a video camera is controlled so as to point to the detected position. Each of the speech-activated transmitters has a microphone that can be used as a sensor. Therefore, where the microphones are used as sensors, it becomes possible to change a photographing method used for the video camera, based on information obtained from the sensors.
Patent Document 2 discloses a target-position search apparatus including a camera and a display unit. The target-position search apparatus receives the position information of a target via a center apparatus and measures the current position, photographing direction, and photographing angle of the camera. Then, the target-position search apparatus determines the position of the target in an image photographed by the camera, based on the measured information, and displays the target position on the photographing image.
According to the known sensing-network systems, all of the sensor modules are set to perform measurement and communications according to the same schedule. Therefore, it is impossible to select a predetermined sensor module and collect information about a predetermined position therefrom.
Although information about the predetermined position can be collected from each of the entire sensor modules, and unnecessary data can be selected and disposed of through an information collection apparatus, the above-described known systems have the following problems.
As a first problem, each of the sensor modules requires a relatively high-capacity battery mounted therein, so as to operate continuously over a long time period. As such, there is a limit to battery downsizing, and therefore it is difficult to downsize the entire sensor module. To solve the above-described problem, research has been conducted on reducing average power consumption of the sensor module by making the sensor module operate intermittently at regular intervals, optimizing the amount of power supplied to each element of the sensor module, reducing power consumption of each element, and so forth. However, an adequate level of power-consumption reduction has not yet been attained.
Also problematic with the above-described known systems is that all the sensor modules transmit the measurement data with equal frequency. Therefore, where multi-hop communications, in which data is relayed in a bucket-brigade fashion, are performed between the sensor modules, the amount of data passing through the sensor module may greatly increase, as the number of relay stations increases. Accordingly, the entire measurement data may not be transmitted at a predetermined data-transfer rate.
According to Patent Document 1, the photographing method is changed based on the information transmitted from the plurality of sensors. Therefore, the method for collecting information transmitted from the sensors cannot be changed based on photographing information indicating the photographing direction or the like.
The system disclosed in Patent Document 2 allows for changing the method for displaying the target on the display unit based on the position information of the target and the photographing information indicating the camera-photographing direction or the like that are transmitted via the center apparatus. That is to say, the above-described system does not allow selecting a predetermined information-acquisition apparatus from among a plurality of information-acquisition apparatuses so as to collect information therefrom and control operations of the information-acquisition apparatuses.